Communication systems include a large number of interconnected components that enable a mobile or fixed device with network access to communicate with other such devices throughout the network coverage area. In a traditional wireline network, telephones or computers located at a home or business are connected by wire or cable with a central office, or switching center, which arranges for a circuit to be established for each call. These circuits are made by the closing of switches throughout the network until a continuous communication path is formed from the calling party to the called party. The various network switches communicate with each other using an established signaling protocol to properly route the call. The circuit remains in place for the duration of the call; when the call terminates, the switches, lines, and other resources are freed for use in other calls.
A wireless communication system necessarily operates somewhat differently. In a wireless system most, if not all calls are placed using mobile devices, meaning that they must communicate over radio frequency channels with a point of access to the communication network that will direct their calls to the appropriate parties. In addition, mobile users may physically relocate during or between communication sessions. Not unexpectedly, these characteristics impose limitations on the capabilities of wireless networks, at least until some manner of accommodating them in various situations can be developed.
One manner of providing additional capabilities to users in the wireless environment was the introduction of SMS (short message service) messages. SMS messages are short text messages of limited length that may be transmitted very quickly to or from a UE (user equipment) device to the network through an available point of access. Advantageously, this transmission can also be done at any time—meaning that SMS transmissions over wireless channels can take advantage of time periods where the traffic level is otherwise quite low. Since they can be sent very quickly, these low-traffic intervals need not be long in duration, and so in most cases will be encountered on an adequate basis without unduly delaying the transmission of the SMS message.
SMS messages have since their introduction become a popular form of communication. Not only can wireless network operators take advantage of the way in which the messages are communicated to the network, but two or more users can communicate effectively even though they are not simultaneously available for a voice call. Indeed, efficient communication is practically enforced by the required brevity of the SMS message. This remains true even though somewhat longer messages are now permitted than was originally the case. The ability to send longer messages has, of course, made SMS messaging even more popular.
Generally speaking, the uses for SMS messages have expanded beyond their original, limited use. As mobile uses across all regions and age segments gain confidence in communicating via text messages, a trend of conducting more sophisticated and personal communications has emerged. Some of these personal communications involve information that the parties would consider confidential, such as financial and medical information. In some cases government agencies, banks or other financial institutions, schools, doctors and hospitals, and so forth, are using text messages to conduct business between themselves and customers or patients. Security is therefore becoming an important consideration—certainly more important than when SMS messaging first began. In many applications it is essential.
While various communication network protocols provide general security for SMS, there remains a danger that a hacker or network service person may be able to observe the content of the messages as they pass through the network. Needed therefore is a manner of ensuring a higher degree of security for SMS messages, especially those transmitted for the purpose of conducting business transactions or exchanging other types of confidential information.